Risk factors for oxygen requirement in hospitalized pregnant and postpartum women with COVID-19

OBJECTIVE: To identify risk factors for Oxygen (O(2)) needs in pregnant and postpartum women with COVID-19. METHODS: Prospective cohort involving pregnant women hospitalized with COVID-19 from April to October 2020. The oxygen need was analyzed regarding risk factors: demographic characteristics, clinical and laboratory parameters at hospital admission, and chest Computer Tomography (CT) findings. Poisson univariate analysis was used to estimate the Relative Risk (RR) and 95% Confidence Intervals. RESULTS: 145 patients, 80 who used and 65 who did not use O(2), were included. Body mass index ≥ 30, smoking, and chronic hypertension increased the risk of O(2) need by 1.86 (95% CI 1.10–3.21), 1.57 (95% CI 1.16‒2.12), and 1.46 (95% CI 1.09‒1.95), respectively. Patients who were hospitalized for COVID-19 and for obstetric reasons had 8.24 (95% CI 2.8‒24.29) and 3.44 (95% CI 1.05‒11.31) times more use of O(2) than those admitted for childbirth and abortion. Respiratory rate ≥ 24 breaths/min and O(2) saturation < 95% presented RR for O(2) requirements of 2.55 (1.82‒3.56) and 1.68 (95% CI 1.27–2.20), respectively. Ground Glass (GG) < 50% and with GG ≥ 50%, the risk of O(2) use were respectively 3.41-fold and 5.33-fold higher than in patients who haven't viral pneumonia on CT. The combination of C-reactive protein ≥ 21 mg/L, hemoglobin < 11.0 g/dL, and lymphopenia < 1500 mm(3) on hospital admission increased the risk of O(2) use by 4.97-times. CONCLUSIONS: In obstetric patients, clinical history, laboratory, clinical and radiological parameters at admission were identified as a risk for O(2) need, selecting the population with the greatest chance of worsening.